1. Field of the Invention
The present invention relates to a magnetooptical recording and/or reproducing apparatus for irradiating a focused light beam on a magnetooptical recording medium and simultaneously applying a magnetic field thereacross to thereby record information thereon or reproduce the recorded information therefrom, and more particularly to a portable magnetooptical recording and reproducing apparatus using a magnetooptical disk cartridge having a magnetooptical disk therein.
2. Description of the Related Art
In general, a magnetooptical disk apparatus has an optical pickup for irradiating a focused light beam and a bias magnet for applying a magnetic field for the recording of desired information. A recording layer is provided in the disk for allowing the recording of information thereonto or reproduction of recorded information therefrom. The recording layer is composed of a magnetic material, for example, terbium ferrum (TbF) or terbium ferrum cobalt (TbFeCo). Such magnetooptical disks are generally enclosed in caddies, the caddy itself being loaded on a disk drive.
In recent years, a magnetooptical disk cartridge, commercially sold as a "mini disk" or MD, has been marketed by Sony (TM). The mini-disk is about 64 mm in diameter, and a player for the mini-disk is currently under ongoing development. There are two types of mini-disks currently on the market, a recordable type mini-disk shown in FIGS. 1A and 1B and a reproduction-only type mini-disk shown in FIGS. 2A and 2B.
Recordable mini-disk 1 has a cartridge shell 2 on both sides of which openings 3 and 4 are formed and a shutter 5 which slides along a sliding groove 6 for the simultaneous opening or closing of openings 3 and 4. A disk 9 in cartridge shell 2 is exposed through openings 3 and 4 on two opposite sides of the cartridge shell.
On the other hand, a reproduction-only mini-disk 1' has a cartridge shell 2' on one side of which an opening 3' is formed and a shutter 5' which slides along a sliding groove 6' for opening or covering opening 3'. In such a device, only one side of disk 9' is exposed via opening 3'.
In each of the above MDs, arrow marks 7 and 7' molded into the upper surfaces of cartridge cells 2 and 2' of mini-disks 1 and 1', respectively, indicate the direction in which mini-disk is inserted into a player. Moreover, cartridge shells 2 and 2' have recognition grooves 8 and 8' of different depths, by which the inserted mini-disk can be identified as being a recordable-type mini-disk or a reproduction-only type mini-disk through a sensor in the recording/reproduction device.
Sony's portable recording/reproducing player (model MZ-1) for mini-disks is currently on the market. This player has a slot for receiving the mini-disk in a slot-in method, a spindle motor for rotating the received mini-disk, an optical pickup for irradiating a focused light beam on one side of the disk, and a magnetic head for applying a magnetic field over the other side of the disk. The cartridge shell of the mini-disk which is received in the slot is loaded on a deck, with the shutter thereof slid open to open the opening. Simultaneously, the disk in the cartridge shell seats on a turn-table which is rotated by a spindle motor. During the rotation of the disk, if a reproduction mode is selected, the magnetic head remains lifted to an "up" position and the optical pickup operates alone. If a recording mode is selected, the magnetic head is lowered to a "down" position by the motor to move together with the optical pickup which nearly contacts the opposite side of the disk. It should be noted that while the reproduction-only mini-disk is loaded, the magnetic head cannot be lowered, even if the recording mode is selected, due to an interlocking device in the player.
General requirements in portable disk players are that they should not only be light and compact, but should also consume low amount of electrical power. However, the Sony players for the use with mini-disks have a very complicated structure which requires a mini-disk inserting mechanism and a mechanism for raising the magnetic head by using a motor. Further, these mechanisms require a large amount of space. Thus, these players cannot be miniaturized or lightened. Also, a relatively large amount of power is required for the insertion or pulling back of the mini-disk and the raising and lowering of the magnetic head.